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<b>DbEnv::close</b>
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<b><pre>
#include &lt;db_cxx.h&gt;
<p>
DbEnv::close(u_int32_t flags);
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<b>Description: DbEnv::close</b>
<p>The DbEnv::close method closes the Berkeley DB environment, freeing any
allocated resources and closing any underlying subsystems.</p>
<p>The <a href="../api_cxx/env_class.html">DbEnv</a> handle should not be closed while any other handle
that refers to it is not yet closed; for example, database environment
handles must not be closed while database handles remain open, or
transactions in the environment have not yet been committed or aborted.
Specifically, this includes <a href="../api_cxx/db_class.html">Db</a>, <a href="../api_cxx/dbc_class.html">Dbc</a>, <a href="../api_cxx/txn_class.html">DbTxn</a>,
<a href="../api_cxx/logc_class.html">DbLogc</a> and <a href="../api_cxx/mempfile_class.html">DbMpoolFile</a> handles.</p>
<p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_LOCK">DB_INIT_LOCK</a>
flag, calling DbEnv::close does not release any locks still held
by the closing process, providing functionality for long-lived locks.
Processes that want to have all their locks released can do so by
issuing the appropriate <a href="../api_cxx/lock_vec.html">DbEnv::lock_vec</a> call.</p>
<p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_MPOOL">DB_INIT_MPOOL</a>
flag, calling DbEnv::close implies calls to <a href="../api_cxx/memp_fclose.html">DbMpoolFile::close</a> for
any remaining open files in the memory pool that were returned to this
process by calls to <a href="../api_cxx/memp_fopen.html">DbMpoolFile::open</a>.  It does not imply a call to
<a href="../api_cxx/memp_fsync.html">DbMpoolFile::sync</a> for those files.</p>
<p>Where the environment was initialized with the <a href="../api_cxx/env_open.html#DB_INIT_TXN">DB_INIT_TXN</a> flag,
calling DbEnv::close aborts any unresolved transactions.
Applications should not depend on this behavior for transactions
involving Berkeley DB databases; all such transactions should be explicitly
resolved.  The problem with depending on this semantic is that aborting
an unresolved transaction involving database operations requires a
database handle.  Because the database handles should have been closed before
calling DbEnv::close, it will not be possible to abort the
transaction, and recovery will have to be run on the Berkeley DB environment
before further operations are done.</p>
<p>Where log cursors were created using the <a href="../api_cxx/log_cursor.html">DbEnv::log_cursor</a> method, calling
DbEnv::close does not imply closing those cursors.</p>
<p>In multithreaded applications, only a single thread may call
DbEnv::close.</p>
<p>After DbEnv::close has been called, regardless of its return, the
Berkeley DB environment handle may not be accessed again.</p>
<p>The DbEnv::close method
either returns a non-zero error value
or throws an exception that encapsulates a non-zero error value on
failure, and returns 0 on success.
</p>
<b>Parameters</b> <br>
 <b>flags</b><ul compact><li>The <b>flags</b> parameter is currently unused, and must be set to 0.</ul>
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<br><b>Class</b>
<a href="../api_cxx/env_class.html">DbEnv</a>
<br><b>See Also</b>
<a href="../api_cxx/env_list.html">Database Environments and Related Methods</a>
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